Recent developments in recalcitrant organic pollutants degradation using immobilized photocatalysts

Immobilization or coating of photocatalysts on supporting media can open a new avenue for industrial application of photocatalysis in wastewater treatment. Herein, we present a critical review of the recent advances in loading photocatalysts on different materials to degrade such bio-recalcitrant organics as pharmaceuticals, pesticides, surfactants, and dyes, which helps in the sustainable use of polluted water after treatment. Many of the recently developed photocatalysts have proven high stability for long periods under illumination. Consequently, employing the catalysts in retained forms provided a viable solution for reuse. Supports may be movable; these include zeolites, polymers, quartz sand, 3-D graphene or fixed, such as glass plates, aluminum plates, and stainless steel plates. Photocatalytic reactors could be an ideal solution for continuous operating treatment, especially in a large-scale operation. In this review, the use of suspended and immobilized systems are compared in the degradation of bio-recalcitrant organic pollutants. Despite the limited research used in the immobilized systems, this proved very successful. This technique has overcome many of the other suspended systems' problems, affording economical solutions such as the possibility of repeated reuse of the catalyst, reduced risk of the catalyst escaping with treated water, and the possibility of application on an industrial scale.

Automated summary

This article compares the use of suspended and immobilized systems in the degradation of bio-recalcitrant organic pollutants. Despite limited research on immobilized systems, it has been very successful. This technique overcomes many problems of other suspended systems, providing economical solutions such as the possibility of repeated catalyst reuse, reduced risk of catalyst escaping with treated water, and the possibility of industrial-scale application.